Process of making lakes from sulfur dyes.



respective dye.

v [UNITED STATES Patented October 25, 1904.

PATENT OFFICE.

RICHARD GLEY, OF BERLIN, GERMANY, ASSIGNOR TOLAOTIEN GE SELL- SCHAFT FURANILIN FABRIKATION, OF BERLIN, GERMANY.

PROCESS OF MAKING LAKES FROM SULFUR DYES.

SPECIFICATION forming part-of Letters Patent No. 7' '7.2,931, datedOctober 25, 1904.

Application filed July 30, 1904. Serial No, 218,853. (No specimens.)

To a whom it may concern.-

Be it known that I, RICHARD GLEY, of Berlin, in the Kingdom of Prussia,German Empire, have invented new and useful Improvements in Processes ofMaking Lakes from Sulfur Dyes; and I do hereby declare that thefollowing is a full, clear, and exact description of .the invention,which will enable others skilled in the art to which it appertains tomake and processcannotbe'applied with practical success to such sulfurdyes which in the presence of alkali sulfids are readily reduced,form

ing either almost-colorless leuco compoundsor such reduction productswhich possess another and very much weaker coloration than correspondsto the shades which are obtain' able when cotton is dyed from thesesolutions. If to these solutions the salt of an earth-alkali metal isadded, the precipitate obtained has only a slight and dull colorationand consists almost entirely of the metal salt of the leuco compound orof the reduction product of the Moreover, I have observed that thisprecipitation is no complete one. a

great part of the leuco compound remaining in solution.

Now I have discovered a new and very simple process which allows theproduction of bright-colored lakes from all these aforementioned sulfurdyes. This new process consists in adding to the'aqueous solution of thesulfur dyes in alkali sulfid the solution of a salt of an earth metal oralkaline-earth metal and precipitating the lake by means of an oxidizingagent in the heat. The simplest oxidizing medium is a current ofatmospheric air, which is blown through the solution; but I may with thelike effect apply hydrogen peroxid, hypochlorid, or the like, onlytaking care to avoid an excess of the oxidizing substance. as aluminiumhydroxid, &c., to the solution before,-during, or after the oxidationprocess. The following examples will show in what manner my process maypractically be carried out: w y

First. Ten partsof immedial sky-blue are dissolved in two hundred andfifty parts of hot water and ten parts of crystallized sodium sulfid. Asolution of twenty parts of sodium carbonate in about one hundred partsof water is then added, and a solution of seventy parts of crystallizedbarium chlorid in three hundred parts of water is poured in. A currentof air is blown through the mixture until the lake is completelyprecipitated. The lake obtained is filtered off with the water anddried. It forms a brilliant blue powder.

Second. Ten parts of immedial sky-blue are dissolved in two hundred andfifty parts of water and ten parts of crystallized sodium sulfid. v Asolution of calcium chlorid containing fifteen parts of CaUIZ is thenadded and eight hundred parts of a paste of aluminium hydroxidcontaining ten per cent. of aluminihydrogen peroxid is added at about 40to centigrade until the precipitation and oxidation is completed. Thelake obtained is washed with water and forms in dry state a blue powder.

Third. Ten parts of immedial indonR cone. and fifteen parts ofcrystallized sodium sulfid are dissolved in three hundred parts ofwater. After addition of a solution of sixty parts of sodium carbonatein three hundred parts of water an aqueous solution containing in fourhundred parts one hundred parts of A12 SO4 3 is poured in, and theprecipitation of the lake is carried out by means of a solution ofhydrogen peroxid. Fourth. Ten parts of'thiogen blueB and fifteen partsof crystallized sodium sulfid are dissolved in two hundred and fiftyparts of water, and a thin paste containing thirty parts of bariumsulfate is added. A solution of twenty parts of crystallized zincsulfate in two I may add a suitable lake base, such um hydroxid. To thismixture a solution of hundred parts of water is poured into the mixture,and the lake is precipitated by introducing a current of air into thehot mixture.

Fifth. Twenty parts of sulfur black T extra are dissolved in fivehundred parts of water by means of fifteen parts, of sodium sulfid. Asolution of twenty-five parts of barium chlorid in one hundred and fiftyparts of water is then added, and a current of air is blown through thesolution at about 60 to 70 until the precipitation is complete and theblack color of the precipitate does not increase in its intensity. Thelake obtained is filtered 01f, Washed, and dried. It forms a deep blackpowder.

It is obvious to those skilled in the art that I may vary theabove-given examples in many respects without departing from the scopeof my invention. For instance, 1 may use strontium or magnesium saltsinstead of barium or calcium salts. It is also apparent that othersuitable lake bases, as those mentioned in the aforesaid examples, maybe used.

N ow what I. claim is-- The process herein described of preparing lakesfrom those sulfur dyes which are converted by alkali sullids inalmost-colorless leuco compounds or in less-colored reduction products,said process consisting in adding to the solution of the dye in alkalisullid a metal salt and precipitating the lake by means of an oxidizingagent, substantially as described.

In witness whereof I have hereunto signed my name, this 18th day ofJuly, 190i, in the presence of two subscribing witnesses.

RlGl'l ARI) (i1 ilCY \Vitnesses:

H IQNRY Hasrnn, "ILLIAM. MAYNnn.

